Earlier this week we talked about how some small businesses in California and elsewhere are seeing health insurance cost increases that may even put them out of business.

What follows are more small business stories that you may find interesting and useful, but first one note: pay special attention if your small business is currently incorporated as an S corporation. There could be big changes on the horizon regarding your tax liability.

This week’s small business news roundup:

Small Business Optimism Reaches Highest Level Since 2008: Beginning the roundup on a positive note is this story out of Gaebler.com, which reports that the National Federation of Independent Business’s “Optimism Index” was up to 92.2 in May — a double digit gain since March 2009. Regarding credit, specifically, 92% of small business owners said their credit needs were being met or that they weren’t interested in borrowing at this time.

The Big Tax Increase Facing Small Business: There’s always something to balance out the optimism, though, isn’t there? This week it’s a report from Forbes.com about legislation making its way through Congress that would hit S corporations in “professional services businesses” particularly hard; the new law is aimed at discouraging the underpaying of the owners of the corporation in order to avoid payroll taxes. If this legislation passes, it would be a huge change to corporate taxation, so keep an eye out here on the blog and in the LegalZoom newsletter for more information.

Small Business Networking: 6 Essential Router Features: Did you know that an average router used for at-home Internet service may not get the job done for your small business? This is a great article from SmallBusinessComputing.com to help you find the best router for your business; you can read about the six most important qualities you should be assessing, and even get examples of three routers that would work well for a small business.